SAN FRANCISCO — No one was injured in an apparent gas-line explosion Wednesday afternoon, but PG&E crews were still trying to shut off gas to choke off a spouting fire almost 90 minutes after the blast.

Shortly after 1:10 p.m., firefighters responded to reports of the explosion and fire near a construction site in the 3300 block of Geary Boulevard at Parker Avenue.

The first call from San Francisco fire dispatchers to firefighters described a “gas rupture,” with “possibly something burning.” About two minutes later, a firefighter reported to dispatch seeing flames shooting skyward from about six blocks away on Masonic Avenue.

At about 1:13 p.m., the first firefighter on scene reported a “gas explosion” and for arriving units to stage a block away and to evacuate people a block in all directions. Firefighters frantically fought the fire initially, directing water onto the adjacent restaurant.

At about 1:24 p.m., a firefighter asked for the arrival time for PG&E and the dispatcher said the utility had been notified.

Firefighters soon called a second alarm, and evacuations and at least one shelter-in-place alert began for nearby buildings and a pre-school and middle school campus.

A third alarm was called just before 2 p.m. Officials said four buildings were affected and at least five workers were accounted for, but they later reported the workers had been located safely and no one had been hurt.

Police also responded to block off traffic along nearby streets.

Vallejo resident Adrian Burrell said he happened to be in a ride-share vehicle nearby when the explosion happened.

“It was right directly in front of us,” Burrell said. “I was talking to the driver and she suddenly screamed. There was fire and flames, and people were running toward the car.”

Burrell said the driver tried to back up, and eventually managed to turn the car around and drive into oncoming traffic lanes to get away.

“It was so big and so crazy. I smelled the gas. I just hope everybody’s okay. You don’t expect something like that to happen,” Burrell said.

“We were at the red light and we were directly behind a police patrol vehicle at the corner. It’s just weird because a couple of moments later and we would’ve been right adjacent to it.”

We are aware that a gas incident has occurred in the #SanFrancisco#Richmond area (3300 block of Geary Blvd). PLEASE AVOID THE AREA. We are working closely w/ first responders and will communicate more as information becomes available. pic.twitter.com/xqsrcBmnyu